"Eating your own dog food", or what I call "dogfooding" refers to using your own products or services while performing your business. For example, 37 Signals uses Basecamp, and Google employees using GMail and Docs, etc. during their own work.

I got a little notification from Trello, informing me of their own Resources. Lots of good ideas and associated tasks there. It's a good example of them using their own product to continuously improve it.